Elon Musk says he’s shooting for a 10-year horizon for the launch of his much-ballyhooed “Interplanetary Transport System,” announced today at an event in Mexico. But he admits it’s a very complicated endeavor to predict a timeline. He’s hoping to establish a steady cadence, much like trains leaving a station, of SpaceX rockets taking off every couple of years.

SpaceX has already tried to have a steady stream of launches. Here is the timeline presented by Musk of SpaceX’s activities over the last decade: